This study examined whether the greater anti-hypertensive efficacy of irbesartan monotherapy over losartan monotherapy extends to the respective fixed-dose combinations with hydrochlorothiazide (HCTZ) in patients with mild-to-moderate hypertension. Patients were treated with either irbesartan 150 mg/HCTZ 12.5 mg or losartan 50 mg/HCTZ 12.5 mg over a 4-week period. Twenty-four hour daytime and night-time mean blood pressure (BP), BP load and duration of action were assessed using ambulatory BP monitoring. Both treatment regimens significantly reduced BP from baseline for all efficacy variables assessed. A significant difference was noted in adjusted mean changes from baseline in 24-h ambulatory diastolic BP with irbesartan/HCTZ versus losartan/HCTZ. Reduction in diastolic load was significantly greater with irbesartan/HCTZ than with losartan/HCTZ as was mean ambulatory systolic BP during the last 4 h of the dosing interval. Both regimens were well tolerated, with no significant differences in terms of adverse event profile observed. Irbesartan 150 mg/HCTZ 12.5 mg resulted in greater reductions in ambulatory BP than losartan 50 mg/HCTZ 12.5 mg.

Hypertension affects approximately 26% of the world's adult population and is a recognized major risk factor for morbidity and mortality associated with cardiovascular, cerebrovascular, and renal diseases. However, despite the availability of a range of effective antihypertensive agents and a growing awareness of the consequences of high blood pressure (BP), the treatment and control of hypertension remains suboptimal. A number of patient subgroups are categorized as 'high risk' and may have hypertension that is more difficult to treat, including obese individuals, patients with stage 2 hypertension, those with type 2 diabetes mellitus (T2DM), patients with coronary artery disease or a history of stroke, and Black patients. As the benefits of lowering BP in patients with hypertension are unequivocal, particularly in high-risk patients, treating high-risk patients with hypertension to BP goals and maintaining 24-hour BP control is important to help reduce cardiovascular risk and improve outcomes. Although the BP goals recommended in current consensus guidelines for the management of patients with hypertension are based on cuff BP measurements, ambulatory BP monitoring (ABPM) provides a valuable diagnostic tool and allows a more accurate assessment of BP levels throughout the 24-hour dosing period. ABPM is a better predictor of prognosis than office BP measurement and is also useful for assessing whether antihypertensive therapy remains effective in the critical last few hours of the dosing period, which usually coincides with the morning BP surge associated with arousal and arising. ABPM has been adopted by new evidence-based guidelines in the United Kingdom to confirm a suspected diagnosis of hypertension, which is an indication of the growing importance of ABPM in the management of hypertension. This review provides an overview of the efficacy and safety of antihypertensive therapy based on olmesartan medoxomil ± hydrochlorothiazide and amlodipine/olmesartan medoxomil in high-risk patient populations enrolled in studies that reported ambulatory BP endpoints. The studies identified in this review showed that a titrate-to-BP goal strategy using olmesartan medoxomil- or amlodipine/olmesartan medoxomil-based antihypertensive therapy was an effective and well-tolerated approach for maintaining BP control throughout the full 24-hour dosing period in high-risk patients with difficult-to-treat hypertension.